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81.
Polycrystalline Cu(In,Ga)Se2 (CIGS) films with various ratios of Cu, In, and Ga were grown by codeposition of all elements in vacuum. The X-ray diffraction
study showed that the films are single-phase and possess a chalcopyrite structure with predominant [112] orientation. The
films exhibited a mirror smooth surface and had a close-packed structure composed of crystallites with clear faceting and
a transverse size of 0.1–0.3 μm. Related surface barrier structures of the (In,Ag)/Cu(In,Ga)Se2 type were obtained and their spectra of the quantum efficiency of photoconversion were studied. The obtained structures can
be used for optimization of the CIGS film technology. 相似文献
82.
A new method has been developed for compressing the matrices that occur in most integral-equation-based computer programs. This method is easy to interface with existing computer programs, and allows them to run significantly faster and with significantly less memory. This method applies not only to electromagnetic and acoustic computation, but also to most programs involving a Green's function or any integral equation with a kernel having some smoothness properties. Our numerical computations, running on a high-end personal computer, have achieved compression ratios of fifty times, and compressed inversion of the matrices fifty times faster than by previous methods. For larger problems, solved on high-performance computers, these ratios would improve to about one thousand to one for larger moment method problems. 相似文献
83.
The emerging software defined radio technologies will be an enabler for a new generation of dynamic wireless systems. It will also open up the possibility of allocating frequencies in a, more dynamic way than today. From an intersystem-interference point of view, this can cause unforeseen problems to occur due to the increased complexity in such applications. In such applications, a measure indicating whether or not a frequency band is possible to use from an electromagnetic interference point of view, must be found. A simple approach is to use the measured total average interference power within the receiver band. Since the interference impact on modern digital communication systems from an interference signal does not only depend on the power but also on the actual waveform of the interference signal, some kind of quality measure of the average-power approach would be convenient to use. In this paper, we introduce a simple quality measure of the average-power approach so that a rough adjustment for the interference-waveform properties can be done. 相似文献
84.
This paper provides an overview of the main aspects of modern fluorescence microscopy. It covers the principles of fluorescence and highlights the key discoveries in the history of fluorescence microscopy. The paper also discusses the optics of fluorescence microscopes and examines the various types of detectors. It also discusses the signal and image processing challenges in fluorescence microscopy and highlights some of the present developments and future trends in the field. 相似文献
85.
Finite element piezothermoelasticity analysis and the active control of FGM plates with integrated piezoelectric sensors and actuators 总被引:3,自引:0,他引:3
An efficient finite element model is presented for the static and dynamic piezothermoelastic analysis and control of FGM
plates under temperature gradient environments using integrated piezoelectric sensor/actuator layers. The properties of an FGM plate are functionally graded in the thickness
direction according to a volume fraction power law distribution. A constant displacement-cum-velocity feedback control algorithm that couples the direct and inverse piezoelectric effects is applied to provide active feedback
control of the integrated FGM plate in a closed loop system. Numerical results for the static and dynamic control are presented
for the FGM plate, which consists of zirconia and aluminum. The effects of the constituent volume fractions and the influence
of feedback control gain on the static and dynamic responses of the FGM plates are examined.
Received: 13 March 2002 / Accepted: 5 March 2003
The work described in this paper was supported by a grant awarded by the Research Grants Council of the Hong Kong Special
Administrative Region, China (Project No. CityU 1024/01E). 相似文献
86.
Seidel A.R. Bisogno F.E. Pinheiro H. do Prado R.N. 《Industrial Electronics, IEEE Transactions on》2003,50(6):1267-1274
This paper presents a simple alternative for an electronic ballast operating in self-sustained oscillating mode with dimming capability for fluorescent lamps. A simple modification in one of the gate drivers side circuit allows the lamp to dim without compromising the simplicity, reliability, and low cost which characterize the self-oscillating electronic ballast (SOEB). A qualitative analysis is presented to explain the behavior of the proposed self-oscillating electronic ballast with dimming feature. In addition, the stability and the key equations for the design are derived using the extended Nyquist criterion and describing function method. Experimental results from two 40-W electronic ballasts are presented to demonstrate the performance and to validate the analysis carried out. 相似文献
87.
N.S. Chen S.F. Yu 《Photonics Technology Letters, IEEE》2004,16(7):1610-1612
The effect of external optical feedback on the transient response of antiresonant reflecting optical waveguide (ARROW) vertical-cavity surface-emitting lasers (VCSELs) is studied. It can be shown that the proper design of ARROW can suppress the excitation of high-order transverse leaky mode as well as increase the critical feedback strength so that stable high-power single-mode operation of VCSELs can be obtained even under the influence of strong external optical feedback. 相似文献
88.
Scale Up from Small Oven-Drying Tests of Mineral Concentrate to Pilot-Scale Drying with a Heated Pad
While Fickian diffusion models are commonly used in other applications, there are few reports of them being applied to the batch drying of a mineral concentrate. Diffusion coefficients estimated from small-scale oven-drying tests were used to predict the drying behavior of a concentrate sample 1 m × 1 m in area and 50 cm deep, with a heated bottom pad. These pilot-scale tests included both daily turning of the sample and turning every three days. The excellent quantitative agreement between the predicted and observed pilot-scale behavior gives a high level of confidence in the model predictions and suggests that a Fickian diffusion model is adequate to predict the behavior of mineral concentrates at the low moisture contents used here. 相似文献
89.
The scale along the coordinate axes in the equations of motion hitherto used for an H-maser (in relative units) is shown to depend on Q as the quality factor for an H-maser. This hinders both analysis of the operation of the H-maser and optimization of its parameters. The modified equations of motion proposed here do not have that shortcoming. We determine the atomic flux into the bulb that gives the H-maser the best metrological characteristics. 相似文献
90.
M. Kawasaki T. Tsukamoto Y. Kimura T. Iwasaki H. Yamane 《Journal of Materials Science》2003,38(4):739-745
The damage imposed on SiO
x
deposited nylon 6 films as a result of abrasion with a cotton cloth and Gelboflex testing was examined by evaluating the rate at which copper plates, which were enveloped by the damaged films, were corroded by H2S. Abrasion with a cotton cloth caused some micro-cracking of the SiO
x
layer and the permeation rate of H2S approached that of the uncoated nylon 6 film. Damage to the SiO
x
layer by twisting and crushing progressed gradually with the number of Gelboflex test cycles and correspondingly the corrosion rate of the copper plates increased. Comparison of the corrosion rates of the copper plates kept in the pouches made of various commercial films with those obtained for the damaged SiO
x
deposited nylon 6 films showed a clear relationship between the H2 permeation rate of the films and the corrosion rate of the copper plates by H2S. 相似文献